Minerals and Rocks UnitWeek 16

Directions1.Prepare your desk for science.2.Use voice level 0 (no voice) to read textbook

pg. 240. Review what color and luster are. Begin to think about what hardness and streak are.

Targets & Warm UpTargets:•Students will use physical properties to identify minerals.

Warm Up: What are color and luster? What do you know about them?

Minerals• Natural, nonliving solid crystals that make up

rocks• Each mineral has crystals that are a particular

shape

How to Identify a Mineral• To identify a mineral, scientists test some of its

physical properties• A physical property is a characteristic of a

substance that can be observed without changing the substance

How to Identify a Mineral

Physical properties scientists use to identify minerals:

ColorLuster

(dull/earthy, glassy, pearly, metallic)

What is the color? What is the luster?

How to Identify a Mineral

Other physical properties scientists use to identify minerals:

StreakHardness

Streak• Streak: the color of the powder of a mineral

• To test for streak, you rub a mineral across a tile of white unglazed porcelain. Then, you examine the color of the streak left behind.

Streak• Streak is closely related to color, but is a

different property• The color of the mineral may be different than

the color of the streak

Streak Video

Hardness

• Hardness: The mineral’s resistance to being scratched

• Mohs Hardness Scale: Scale of 1 to 10 measuring mineral hardness– Larger number = harder– Smaller number = softer

Mohs Scale of Hardness

Hardness

• We can use everyday items to help us test the hardness of minerals.

• Fingernail = 1 or 2• Penny = 3 to 5• Paperclip = 5 or 6

** If none of these items can scratch the mineral, than its hardness is a 7 or above!

Hardness• How to test for hardness:

– A fingernail has a hardness of 2.– A copper penny has a hardness of 3.– The paperclip has a hardness of 5.

• SOFT: Minerals that can be scratched with a fingernail.• MEDIUM: Minerals that can be scratched by a copper penny.• HARD: Minerals that cannot be scratched with a steel

paperclip

Hardness Video

Your Task• What is the streak of the minerals in front of

you?– Can you see a streak?– Is the streak the same color as the mineral?

• What is the hardness of the minerals in front of you?

Scratched by a fingernail?

Scratched by a penny?

Scratched by a paperclip?

Soft yes yes yesMedium no yes yes

Hard no no yes or no

Extra Time?

Read pg. 240-241

Reflection Questions

• What physical properties do scientists use to identify minerals?

• What physical properties are observable with your eyes?

• What physical properties need to be done in a hands-on test?

Targets (Revisited)

Targets:•Students will use physical properties to identify minerals.

Homework

Subject Homework Due DateScience Minerals worksheet

(2 sides)Monday

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